A Known Variable
by Lialane Graest
Summary: There must always be a control in an experiment. When a known variable is introduced to Stein's research, can he handle it?


There is very little of Stein's rational mind left when he falls to the madness. The shreds that he retains access to are normally comprised solely of his medical knowledge; something that makes him a very, very dangerous person to be alone with when he is lost. She has never feared him; she would never choose to run. He knew that, knows that, and unfortunately for her, he also knows where she is.

He knows when she sleeps, he knows what her favorite food is, what she tends to drink in the morning before classes, what she drinks to help sleep at night. He knows what perfume she wears; he knows what makeup she uses, down to the shade of the lipstick. He knows everything about her, having lived with her for over a year now. He is as intimately familiar with her wavelength as his own at this point.

Her muffled sobs mean less to him than this wealth of unexpected knowledge. Some part of him still knows who she is, but he locks that away. To associate with a participant in an experiment with the knowledge that you know them would ultimately cause the experiment to fail. He locks away the information on her that is irrelevant to the experiment he was conducting and paces outside the room she is in.

Her voice is angry, but he refuses to allow himself to refer to her as Marie. _'The subject's voice displays anger,'_ he mentally corrects himself; his hands clench into fists at referring to Marie as 'the subject' but he doesn't know why.

It doesn't matter anyway.

She became a willing participant in the experiment the moment that she moved in with him. He had pushed the deadline for it back again and again, knowing that she would never approve of his methods, but after a year she was still there; she was still in his way hampering his research.

Ah, yes. The subject in question was hindering his ability to proceed. Therefore, the subject must be anesthetized so that he could continue with his research. It is actually quite imperative, lest she disturb his research yet again…

What is his thesis again? Ah, yes.

It is on the effects of prolonged sensory deprivation on the human psyche, and any degradation in the strength of their soul's wavelength that appeared to be linked to the time that they spent with a single sense deprived of them.

He will need multiple subjects, of course. He knows that they will be easily acquirable, however, and he has one now that is perfect for his current course of study.

"Subject is exhibiting anger," he says slowly, a smirk tugging at the corners of his lips. "I believe that this is in direct response to the removal of her good eye. I will make certain that she is well compensated for her participation of course." His finger slides off the record button and he glances over at the door to Marie's room before pressing it again. "I am unsure of whether she fully understood what she was agreeing to, however. Regardless, I have her consent here."

He glances down at the document he holds crumpled in his hand. Something rushes through him, screaming that the document isn't a consent form. He shakes his head, his eyes unfocused as her name repeats itself time and time again in his mind, images of her in a white dress before an altar flashing with it.

Consent form or marriage certificate, that is irrelevant knowledge to the current experiment and so he files it away. It can be dealt with later.

"Subject refuses to leave her room, indeed, she has barricaded the door with what I can only assume is the bed. Quite the feat for someone that is for all intents and purposes completely blind now. She needs to be anesthetized, but I cannot enter the room by normal means. If the empty socket is not properly cleansed, she may develop an infection, and that would be counterproductive to my research."

Empty air fills a few moments on the tape before he speaks again. "I am dealing with bothersome emotional attachments to the subject, including the urge to refer to her by name. It is unknown what is causing this response in myself. I believe that it may have something to do with the subject's wavelength and I intend to include any insight I gather on the phenomenon in my dissertation."

He lets his finger slide off the record button again and twists the screw in his head, trying to clear the cloying emotions that are threatening to become a hindrance to his research. He cannot grasp why this subject is being so bothersome to him; none of the others he has used have evoked this amount of emotion from him.

Emotions are useless in the realm of science. What he needs are facts- black and white, irrefutable facts. And the only way that he is going to get the facts that he needs to continue his research is to sedate his current subject.

Her voice comes through the door, barely heard, tear filled. It is no longer raised in anger; it seems to be hushed, almost as if she is whispering.

Something akin to fear floods through him, adrenaline coursing through his body. The change in her tone forces him to action. His wavelength shines around his hands as he grabs the doorknob, the metal shattering and slashing his palm as he forces the barricade that she had built up back.

He sees her immediately, her right hand pressed against the empty eye socket that he needs so desperately to clean. A yellow phone is pressed against her left ear, and despite her lack of sight she jerks her head towards him as he enters.

He can hear a voice, loud and demanding, coming from the phone. She cringes from him as he darts to her, his hand wrapping around hers, fingers digging into pressure points to force her to release the phone.

Her voice cries out, shrill and desperate, as the phone falls to the ground. "Sid, send help!"

He has backhanded her before he realizes what he has done. The violence of the motion freezes him for a moment, his eyes unfocused and staring at the woman lying on the floor, fresh blood trickling from the back of her head.

"Ma-rie-" he begins, his hand sliding up to the screw in his head, a slight trembling passing through it before he calms. "No," he corrects himself, his hand falling from the screw without twisting it, "the subject, has breached the terms of consent and contacted an outside party. She has forfeited any type of payment for this- indeed, according to the terms that were signed she is no longer eligible to be used as a participant in this experiment."

Marie looks up, fear in her features as the weight of his words crashes over her. She reaches out blindly, hoping that he is close enough to touch, knowing that only her wavelength can save her now.

Her hand meets empty air. She would cry if she could, her breath hitching as if she is. She struggles to her feet, the room as still and quiet as if it were empty. She has only a moment of thought, his name exploding from her in a rush as his hand slams into her back and sends her crashing into the wall.

He moves over to her, looking down at the feebly breathing woman. "The subject was a known variable in any case. It is a shame that I must terminate this part of my thesis' research, but the advancement of science must go on."

"Franken…" she coughs weakly as he towers over her.

* * *

A pounding noise resounds through the Lab, but no one goes to the door. Sid shoulders the door open, rushing through the dimly lit halls, calling out Marie's name every few strides. Nygus is held at the ready in his hand, the zombie slowing down as he approaches the deeper rooms of Stein's Lab.

"Marie?" he calls out, sliding around the corner, his own _Soul Perception_ detecting nothing. He wonders if Stein has found a way to camouflage his wavelength, a chill of fear running down the zombie's spine.

He continues to move through the silent lab, and stops outside Marie's room when he arrives there. A trail of blood runs along one wall leaving it, but he still cannot sense any other souls near his.

A sudden sound behind him, from inside Marie's room, makes him whirl, Nygus at the ready. A sheaf of papers has become unbalanced, probably from the wind, he thinks, and has fallen to the floor. Sid picks it up, another shiver running down his spine.

The original title of the paper has been crossed out; written in a slightly sloppy hand in its place is, '_The Problems of a Known Variable- their cause and outcome by Dr. Franken Stein'._

Sid drops the papers when he realizes that it is not red ink but blood that it has been written in. He moves quickly to search for them again, but can find no trace of Marie or Stein's souls.

* * *

**A/N: Yes, it has been a while. Yes, this one was intentionally left open for your interpretation of what has happened. Do you believe he killed Marie? Did he come to his senses? I hope that you've enjoyed this. As always, I don't own Soul Eater.**

**/Lialane**


End file.
